STOCK-BASED COMPENSATION PLANS - Summary of Stock Option Activity (Details)	12 Months Ended
Dec. 31, 2018 $ / shares shares
Shares
Granted (in shares)	0
Stock options
Shares
Balance, December 31, 2017 (in shares)	379,000
Granted (in shares)	0
Exercised (in shares)	(6,000)
Forfeitures and post-vesting cancellations (in shares)	(150,000)
Balance, December 31, 2018 (in shares)	223,000
Exercisable, December 31, 2018 (in shares)	211,000
Weighted Average Exercise Price
Balance, December 31, 2017 (in dollars per share) \| $ / shares	$ 21.17
Granted (in dollars per share) \| $ / shares	0.00
Exercised (in dollars per share) \| $ / shares	8.49
Forfeitures and post-vesting cancellations (in dollars per share) \| $ / shares	14.55
Balance, December 31, 2018 (in dollars per share) \| $ / shares	25.95
Exercisable, December 31, 2018 (in dollars per share) \| $ / shares	$ 26.74

The number of shares into which fully or partially vested stock options outstanding as of the balance sheet date can be currently converted under the option plan.

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The weighted-average price as of the balance sheet date at which grantees can acquire the shares reserved for issuance on vested portions of options outstanding and currently exercisable under the stock option plan.

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For presentations that combine terminations, the number of shares under options that were cancelled during the reporting period as a result of occurrence of a terminating event specified in contractual agreements pertaining to the stock option plan or that expired.

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Weighted average price of options that were either forfeited or expired.

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Gross number of share options (or share units) granted during the period.

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Number of options outstanding, including both vested and non-vested options.

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A roll forward is a reconciliation of a concept from the beginning of a period to the end of a period.

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Weighted average price at which grantees can acquire the shares reserved for issuance under the stock option plan.

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Weighted average price at which option holders acquired shares when converting their stock options into shares.

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Weighted average per share amount at which grantees can acquire shares of common stock by exercise of options.

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Number of share options (or share units) exercised during the current period.

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